A Pertiwi, E Widodo, M Nur Ikhsan and B Sundu1

Abstract

Raw feather waste has been an environmental problem as the production of
feather has been increasing from year to year due to increased population of
poultry. Since feather meal is considered to be a low quality feedstuff,
hydrothermal processing with enzymatic treatment is one of the ways to
improve its quality Two studies were conducted to determine the effects of
enzymatically hydrolyzed feather meal (EFM) on feed intake, body weight
gain, feed conversion ratio (FCR), carcass weight and carcass percentage
(Experiment 1), feather percentage and total number of pinfeathers
(Experiment 2). In experiment 1, a total of 108 day-old local Bali ducks
were used and placed in the pens and the same number of ducks was used in
the experiment 2. The ducks were kept for 10 weeks and fed the experimental
diets. The experimental diets were the same in both experiments; CTL:
control basal diet, EFM01: basal diet + treated feather meal with 0.01%
enzyme (Allzyme FD) and EFM02: basal diet + treated feather meal with 0.02%
enzyme. Parameters measured were feed intake, protein intake, body weight
gain, feed conversion ratio and carcass percentage in experiment 1 and
feather percentage and number of pinfeathers in experiment 2. A completely
randomized design was used with 3 different treatment diets and 6 replicate
cages in both experiments. Any significance found in the analysis of
variance was further tested by Tukey Test.

Results indicated that the supplementation of the diets with enzymatically
hydrolyzed feather meal (EFM01 and EFM02) improved feed intake, protein
intake, body weight gain, feed conversion ratio and carcass percentage.
Ducks fed EFM02 had better body weight gain and FCR than those of ducks fed
the EFM01. In experiment 2, ducks fed the enzymatically hydrolyzed feather
meal had more and heavier feather production at weeks 7 and 8, but less
numbers of protruding pinfeathers and non-protruding pinfeathers than those
ducks fed the control basal diet.

In conclusion, the supplementation of the diets with enzymatically
hydrolyzed feather meal increased duck performance, carcass percentage and
feather percentage and decreased total number of protruding pinfeathers and
non-protruding pinfeathers.

Keywords: enzyme, performance, pinfeathers

Introduction

Demands for meat duck in Indonesia have slightly been increasing over the
last two decades, from 25,782 ton in 2009 to 36,346 ton in 2015 (Dirjen
Peternakan dan Kesehatan Hewan 2015). Supplies of ducks for meat were
previously from culled local ducks reared for eggs. Scavenging herding
system is still commonly practiced and contributed most of the duck meat in
the Indonesia’s market. Since the duck meat business is a rural based and
practiced by small holder farmers, the duck meat industry is relatively
small in comparison to the broiler industry. The slow growth of duck
industry in Indonesia was partly due to low production and carcass quality
as Indonesia’s duck industry relies much on local ducks, with commonly
having black or dark feather. These particular dark color ducks are commonly
found in tropical countries as ducks need to be able to adapt with high
intensity of sunlight (Galvan and Solano 2016).

The appearance and quality of carcass can determine preference of consumers.
The dark color feather is not preferred by the consumers due to the fact
that pinfeathers were still left on the carcass of duck after commercial
de-feathering. Mechanical pluckers with revolving tuber finger were usually
used to remove most of the feathers. A lot of dark / black feather follicles
(pinfeathers) left on the skin (protruding pin feathers) or just below the
skin (non-protruding pinfeathers) produced carcasses that look dirty. To
have the carcass free from pinfeathers takes much time as these pinfeathers
must be removed by hand. There is scarcely practical solution for the
removal of pinfeathers unless the ducks were kept much longer up to all the
pinfeathers growing longer. However, this solution creates problem of meat
toughness of older ducks.

Nutritional approach might be able to cope with the problem of dirty carcass
by accelerating the growth of duck feathers, including the pinfeathers. This
can be made by providing nutrients matching to the nutrients profile of
feathers. The uses of feather meal in poultry diets have been practiced for
decades. The uses of this waste product in the diet are not only to supply
the nutrients for feather growth but also to minimize environmental
pollution of poultry waste material. The problem of poultry waste has been a
main concern in Indonesia since Indonesia is one of the largest poultry
producer in the world, with a total production of 3,2750.000 tons in 2015
(Dirjen Peternakan dan Kesehatan Hewan 2015). This is equivalent to 32,750
tons feather meal production in 2015 (Rutkowski et al 2003).

Although the protein profiles of feather meal is matching to the feather
growth, most of the protein in feather meal (90%) is in the form of keratin,
which is categorized by high stability and low solubility due to the
presence of Sulphur to Sulphur bound between cysteine amino acids (Brebu and
Spiridon 2011). Accordingly, this waste product is regarded a low quality
feedstuff. Treatments to improve the quality of feather meal have been done
through fermentation (Mulia et al 2016), chemical treatments (Staron et al
2014), Hydro-thermal application (Kormanjos et al 2015) and enzymatic
treatment (Rutkowski et al 2003). The aim of these treatments is to disrupt
the structure of keratin in feathers to make the protein available to non
ruminant animals. Two studies have been carried out to determine the effect
of feather meal treated with enzyme on duck performance, carcass percentage
and feather growth.

Materials and methods

Production of enzymatically hydrolized feather meal.

The waste of broiler’s feather was collected locally from broiler slaughter
house. The wet feathers were gathered and cleaned from any foreign
contamination such as blood, feed material and excreta. The feathers were
oven-dried for three consecutive days at 60oC. A total of 100 and
200 g enzyme (Allzyme FD) were diluted in 50 ml tap water and sprayed onto
the 10 kgs dried feather meal to have 0.01 and 0.02% inclusion of enzyme
respectively. During spraying, the feather meal was stirred evenly. The
mixtures between enzyme and feather meal were placed into an autoclave
previously heated to 60oC for 20 minutes. After 1 hour the
temperature was raised at120oC with 2.5 atmospheres. The feather
was then oven dried for 3 days at 60oC prior to grinding with
hammer mill. Enzymatically hydrolyzed feather meal EHFM was produced and
used as a feedstuff.

Ducks and feeds

A total of 108 day-old male Bali ducks were purchased locally and used as
experimental animals for growth and carcass study (Experiment 1) and another
108 day-old male Bali ducks were used for feather growth study (Experiment
2). The ducks were allocated in the three brooder cages for 2 weeks based on
treatments and then transferred into 18 pens. The animals were kept for 10
weeks.

Experimental diets

The experimental diets used in this study are shown in Tables 1 and 2. The
nutrient contents of the basal diet were based on NRC (1994). The ducks were
allowed to consume the basal and treated diets. Water and feed were supplied
at all times throughout the study.

Table 1.
Composition of the experimental starter diets (%)

Ingredients

CTL

EFM01

EFM02

Soybean meal

28,0

26.6

26.6

Maize

57,7

54.8

54.8

Fish meal

9.0

8.6

8.6

Rice bran

2.0

1.9

1.9

Copra meal

2.0

1.9

1.9

Palm oil

0.0

0.0

0.0

Dicalcium phosphate

0.10

0.10

0.10

Limestone

0.10

0.10

0.10

Salt

0.2 0

0.19

0.19

Lysine

0.50

0.47

0.47

Vitamin and Mineral Mixture

0.40

0.38

0.38

Enzymatically Hydrolyzed feather meal

0.0

5.0

5.0

Calculated:

Crude protein

22.8

25.7

25.8

Crude fibre

4.9

4.7

4.7

ME (K Cal/kg)

2905

2877

2876

Lysine

1.18

1.24

1.25

Methionine

0.18

1.20

1.21

Calcium

0.77

0.75

0.75

Phosphorus

0.7

0.69

0.69

Table 2.
Composition of the experimental grower diets (%)

Ingredients

CTL

EFM01

EFM02

Soybean meal

15.0

14.3

14.3

Maize

53.2

50.5

50.5

Fish meal

7.2

6.8

6.8

Rice bran

3.9

14.4

14.4

Copra meal

5.2

4.9

4.9

Palm oil

2.0

1.9

1.9

Dicalcium phosphate

0.63

0.60

0.60

Limestone

0.53

0.50

0.50

Salt

0.27

0.26

0.26

Lysine

0.30

0.29

0.29

Vitamin and Mineral Mixture

0.47

0.45

0.45

Enzymatically hydrolysed feather meal

0

5.0

5.0

Calculated:

Crude protein

17.0

20.2

20.3

Crude fibre

4.7

4.5

4.5

ME (K Cal/kg)

3002

2969

2970

Lysine

0.84

0.91

0.91

Methionine

0.19

0.21

0.21

Calcium

1.01

0.98

0.98

Phosphorus

0.7

0.69

0.69

Parameters

The parameters measured in Trial 1 were feed intake, dry matter intake, body
weight gain, feed conversion ratio, carcass weight and carcass percentage.
At the end of the experiment, fifty four ducks (3 birds per replicate cage)
were randomly selected for carcass measurements. The ducks were killed by
cervical dislocation and dressed by removing the feathers using mechanical
plucker. The eviscerated ducks were dressed by removing the neck, the shanks
and the internal organs. The dressed ducks (carcasses) after manually
removing the pin feathers were weighed and recorded.

In Trial 2, the measurement of feather growth was done at weeks 7, 8, 9 and
10 by slaughtering six ducks (one duck per experimental unit) per week. The
parameters were total feather weight, feather percentage, total number of
protruding pinfeathers and non-protruding pin feathers left after mechanical
de-feathering. Protruding pinfeathers are the pinfeathers which have broken
through the outer layer of skin, while non-protruding pinfeathers are the
pinfeathers which have not pushed through the outer skin. The slaughtered
ducks were eviscerated and dressed. The protruding pin feathers and
non-protruding pin feathers of the dressed ducks were manually removed by
hand and coun them all.

Statistical analysis

The two studies used a completely randomized design with three treatment
diets and six replicate cages of 6 ducks each cage. Data collected from the
studies were analyzed by analysis of variance using a Minitab14 Statistical
Program (Minitab 2003). Differences among treatment means found in the
analysis of variance were further tested by Tukey Test (Steel and Torrie
1980).

Results and discussion

The effect of enzymatically hydrolyzed feather meal in the broiler chicken
diet on feed intake, body weight gain, feed conversion ratio (FCR), carcass
weight and carcass percentage are shown in Table 3. The supplementation of
the diets with enzymatically hydrolyzed feather meal improved feed intake,
body weight gain, FCR, carcass weight and carcass percentage. Data on
feather percentage, feather weight, number of pinfeathers, either protruding
pinfeathers or non-protruding pinfeathers of the ducks at 7, 8, 9 and 10
weeks old fed the control diet and enzymatically hydrolyzed feather meal can
be seen in Table 4. Feather percentage of ducks at 7 and 8 weeks old were
higher in ducks fed the diets containing enzymatically hydrolyzed feather
meal, but not in 9 and 10 weeks old ducks. Feather weight of ducks fed the
feather meal treated with 0.01% enzyme (Allzyme FD) had heavier feather
weight than those of the control ducks at all ages (7, 8, 9 and 10 weeks).
The diets fed the enzymatically hydrolyzed feather meal had less protruding
pin feather or non-protruding pin feather than those of the ducks fed the
control diet.

Duck performance

The efficacy of using enzymes to improve the quality of the diet has been
succesfully used in palm kernel meal diet (Iyayi and Davis 2005), soybean
(Jackson et al 1999), barley (Classen et al 1985) and copra meal (Sundu et
al 2008). The results of the current study on the effect of enzymatically
hydrolyzed feather meal add up this consistency. Ducks fed the enzymatically
hydrolyzed feather meal (EFM01 and EFM02) had higher body weight gain than
the ducks fed the control diet (CTL). This might be due to the fact that
ducks fed the enzymatically hydrolyzed feather meal diet ate more than the
ducks fed the control diet, particularly in protein intake. Our study on
digestibility of the same diets indicated that there was an improvement in
metabolizable energy from 3257 kcal/kg for control diet to 3281 kcal/kg for
either 0.01% or 0.02% of feather meal treated with Allzyme FD (Pertiwi,
unpublished). The improvement in metabolizable energy, along with an
improved protein intake might play roles of the increased body weight gain.
Among the ducks fed the enzymatically hydrolyzed feather meal (EFM01 and
EFM02), the supplementation of the diets with feather meal treated with
0.02% Allzyme FD (EFM02) had heavier body weight than the ducks fed the
feather meal treated with 0.01% Allzyme FD (EFM01). Interestingly, this
increase was nothing to do with feed intake since the ducks fed the feather
meal treated with 0.02% Allzyme FD (EFM02) consume less diets than the ducks
fed the diets supplemented with feather meal treated with 0.01% Allzyme FD
(EFM01). This possibly indicates that there was an improvement in feather
meal quality due to an increased concentration of enzyme in feather meal
diet. Yuan et al (2008) found that relative activity of amylase in pancreas
was increased by adding more enzyme in the diet. This might elaborate higher
concentration of enzyme inclusion in the diet positively influence the
quality of the diet.

Our findings also indicated that feed intake was also increased because of
the supplementation of enzymatically hydrolyzed feather meal. The increase
in feed intake was associated with an increase in body weight as heavier
ducks consume more feed. It is not difficult to rasionalize this finding,
due to the fact that the digestive tract on heavier ducks was bigger and
thus could accommodate more digesta. Another possible reason is that
increased feed intake might indicate that diet containing enzymatically
hydrolyzed feather meal (EFM01 and EFM02) would speed up the flow
of the digesta in the digestive system of broilers (Sundu 2009). Feed
conversion ratio was also improved due to the supplementation of the diets
with feather meal treated with Allzyme FD. It is understandable that when
the body weight gain increased, FCR was improved.

Carcass percentage

The supplementation of the diets with feather meal treated enzyme increased
carcass weight from 710 g (control ducks) to between 841 g and 860 g for
ducks fed the enzymatically treated feather meal. The inclusion of 5%
enzymatically hydrolyzed feather meal in the diet increased protein
concentration of the diet by about 3%. The increase in protein diet due to
feather meal inclusion probably helped to increase protein intake and
availability for muscle growth and thus increase in carcass weight. It is
also clear from the data that carcass weight curvilinearly improved over the
increased enzyme concentration of treated feather meal (Y= 718.9 X
0.181; R2= 0.89). However, the
increase in enzyme concentration from 0.01% (EFM01) to 0.02% (EFM02) did not
enhance feather weight.

Ambara et al (2013) fed Bali duck with commercial diet and found that
carcass weight of Bali duck at 9 weeks old was 865.5 g. These current
findings indicate that the Bali ducks fed 5% enzymatically hydrolysed
feathre meal in the diet were smaller than the previous findings of Ambara
et al (2013). The difference in carcass weight was possibly due to different
quality of diet in which Ambara et al (2013) used commercial diet while this
present study used diet containing feather meal treated enzyme.

The same trend was also found in carcass percentage as carcass percentage is
highly correlated to carcass weight. The inclusion of enzymatically
hydrolyzed feather meal in the diet increased carcass percentage by about
1.8 to 1.9%. Increasing concentration of enzyme when treated to feather meal
did not improve carcass percentage.

Feather growth

Wiradhana et al (2013) reported that Bali ducks at 10 weeks, feathers
accounted for 6-7% of body weight. The percentage of feather in this current
study was much lower, only about 3%. A couple of possible reasons related to
the different feather percentage were experimental diets used and the
temperature. We conducted our study at Palu Central Sulawesi, located
exactly in the equatorial line which had warmer temperature (35 oC
during the day) than the study site of Wiradhana et al (2013). The cooler
temperature, coupled with the commercial diets used by Wiradhana et al
(2013), produced ducks with more and heavier feather than our current
findings.

Table 4.
Feather percentage, feather weight and number of
pinfeathers of ducks fed the diets supplemented with or
without enzymatically hydrolysed feather meal.

Feather percentage of ducks fed the diets with enzymatically hydrolyzed
feather meal (EFM01 and EFM02) was higher than the control ducks at weeks 7
and 8. However, when the ducks got older (weeks 9 and 10), feather
percentage of all ducks were statistically the same. The rationale of the
increase in feather percentage of ducks fed the control diet at weeks 9 and
10 may be through a couple of reasons. First, when ducks got older, they
consume more feed and thus more nutrients intake. Higher nutrients
consumption of older ducks might be enough to produce an optimal feather
growth. Second, this is only a matter of proportion of feather weight to
body weight. Since the control ducks grow more slowly, in terms of body
weight, feather percentage at weeks 9 and 10 was high and thus closed to
those ducks fed the enzymatically treated feather meal. However, ducks fed
the feather meal treated with 0.01% enzyme concentration had more and
heavier feather than those of ducks fed the control diets at all ages
(weeks, 7, 8, 9 and 10). The increase in feather percentage of ducks at
weeks 7 and 8 might indicate that feather growth of ducks fed the
enzymatically hydrolyzed feather meal (EFM01 and EFM02) was earlier and
faster than those ducks fed the control diets in weeks 7 and 8. This is
understandably due to the fact that diets with feather meal provide more
amino acids, (particularly threonine and methionine) that are needed for the
growth of feather.

The effect of diets on the growth and number of pinfeathers of ducks has not
been reported in the data base. The presence of pinfeathers on the carcass
made the carcasses look dirty and downgrade carcass quality. Accordingly, to
improve carcass appearance and quality, the carcass should be free from
pinfeathers. The number of protruding pinfeathers and non-protruding
pinfeathers of ducks fed the control diets (CTL) was more than those ducks
fed the enzymatically hydrolyzed feather meal diets (See Picture 1). This
indicates that the quality of the carcass of ducks fed the control diets was
adversely affected due to the presence of high number of pinfeathers.
Supplementation of the diets with feather meal treated with enzyme decreased
the number of protruding pinfeathers by about between 32 and 39% and
non-protruding pinfeathers by about between 39 and 48% at week 10. It can be
said that the supplementation of the diets with feather meal treated enzyme
speeded up the growth of feather and thus made feathers grow longer. The
long feather would be easily plucked during the mechanical de-feathering
process and made the carcass of ducks fed enzymatically hydrolyzed feather
meal had less pinfeathers. Accordingly, this particular treatment could
produce better quality of carcass.

Conclusions

Carcass percentage and carcass weight was improved due to supplementation
of the diet with enzymatically hydrolyzed feather meal.

Ducks fed the diets containing feather meal treated with 0.01% enzyme
produced heavier feather than those ducks fed the control diet.

The number of protruding pinfeathers and non-protruding pinfeathers of
ducks fed the diets supplemented with enzymatically hydrolysed feather meal
was less than the ducks fed the control diets.

Acknowledgements

The authors wish to express special thanks to The head of department of
Animal Husbandry, The University of Tribhuwana Tungga Dewa, Malang, for
providing us research facilities. We are indebt to the Ministry of Research,
Technology and Higher Education for financial support of this experiment.